JP2006065923A - Recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform post-recording including sound monitoring (while reproducing sound) by using a device which cannot execute simultaneous sound coding/decoding. <P>SOLUTION: This recording device temporarily records post-recording signals in a format (with light processing load) different from the standard post-recording format. Later, it converts the signals into the standard format after the post-recording, or converts it into the standard format by simplifying the processing in the decoder (coding while the decoder is sleeping), or to decide the post-recording mode (with sound monitor, without sound monitor, or no post-recording) depending on the remaining quantity of the recording medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording apparatus, and more particularly to an after recording process.

  Currently, DV tape is used as a recording medium in an imaging apparatus such as a digital video camera. In a digital video camera having a DV tape as a recording medium, after-recording (hereinafter referred to as “after-recording”) can be performed by recording an audio signal in an after-recording area provided in advance on the DV tape. Many patents have been filed.

  On the other hand, recording media other than DV tapes include optical disks such as DVDs and Blu-ray disks, hard disks, and silicon memories. In consideration of random accessibility and compatibility with a PC, the recording medium of a digital video camera is expected to shift to an optical disk or the like. At that time, it is considered that a digital video camera having an optical disk as a recording medium also has a demand for an after-recording function like a DV tape.

  Further, in an imaging apparatus using a DV tape as a recording medium, it is difficult to perform post-recording (after-recording with an audio monitor) while reproducing an audio signal recorded on the DV tape due to the structure of the recording / reproducing head. However, when an image pickup apparatus using a disk as a recording medium is used, post-recording recording with an audio monitor becomes possible.

  When an after-recording recording is performed by an image pickup apparatus that performs recording / reproduction with respect to an optical disk, a signal (hereinafter also referred to as an after-recording stream) to be added to a reproduction signal (hereinafter also referred to as an original stream) from the optical disk is added to this signal. There is a method of overwriting or recording on the optical disc. In addition, when the video signal and the audio signal are multiplexed, they are separated, the input signal is added to the separated signal, multiplexed again, and additionally recorded (see, for example, Patent Document 1). .

Also, there is a method of recording an after-recording stream in a different area from the original stream recorded on the optical disc so that the time stamps coincide between the after-recording stream packet and the original stream packet (for example, Patent Documents). 2).
JP 2003-32606 (page 3) JP-A-11-298845 (5th page)

  However, the following problems exist in the configuration of the above prior art.

  When trying to realize the processing shown in Patent Document 1 and Patent Document 2 which are the prior arts, while decoding / reproducing an original stream, an audio signal input from a microphone or the like provided in a digital video In order to perform encoding / recording, it is necessary to simultaneously perform encoding processing and decoding processing inside the recording apparatus.

  Recently, high-efficiency encoding schemes such as MPEG-Audio and Dolby-AC3 have been used instead of PCM (Pulse Code Module) as an audio signal encoding scheme. These encoding methods require a larger amount of calculation processing than the PCM method, and if an encoding / decoding process is to be performed by a processor such as a DSP, an operation with a high clock is required, leading to an increase in power consumption. . Even when processing is performed not by software processing by a processor but by hardware, the encoding circuit and the decoding circuit need to be operated at the same time, so that the same phenomenon as the processor processing occurs.

  Therefore, the present invention provides a recording apparatus that solves such problems and enables easy after-recording recording while monitoring the reproduced sound even when the audio signal is recorded with high efficiency encoding. With the goal.

  In order to achieve such an object, in the present invention, the encoded video signal and the first audio signal encoded by the first audio encoding method are recorded as a multiplexed signal sequence. Reproducing means for reproducing the multiplexed signal sequence from the recorded recording medium, first audio decoding means for decoding the first audio signal in the multiplexed signal sequence reproduced by the reproducing means, and second A voice input unit for inputting a voice signal and a second voice signal input by the voice input unit are encoded by a second voice encoding method having a smaller calculation amount than the first voice encoding method. Second audio encoding means, recording means for recording the second audio signal encoded by the audio encoding means on the recording medium, and an after-recording audio signal to be reproduced instead of the first audio signal After recording mode to record The encoding process by the second audio encoding unit is performed while the reproduction process of the multiplexed signal sequence by the reproducing unit and the decoding process of the first audio signal by the first audio decoding unit are performed. And a control means for controlling the second sound encoding means and the recording means so as to record the second sound signal encoded by the second encoding method on the recording medium.

  According to the present invention, an audio signal encoded by an encoding process with a small amount of calculation can be recorded as post-recording audio while monitoring the audio signal reproduced from the recording medium.

  The best mode for carrying out the present invention will be described below based on examples.

  A first embodiment will be described with reference to the drawings. 1 is an overall system configuration diagram in Example 1, FIG. 2 is a flowchart for explaining the present embodiment, FIG. 3 is a recording medium diagram for explaining the first example, FIG. 4 and FIG. FIG. 5 is a diagram showing an operation state of each block of the present apparatus during post-recording.

  The first embodiment is a form in which a video signal is encoded with MPEG2 and an audio signal and an after-recording signal are encoded with AC3 and recorded on a recording medium such as an optical disk, and a specification capable of simultaneously executing encoding / decoding of an audio signal is provided. A preferred embodiment for performing post-recording while reproducing an audio signal recorded on a recording medium even in a digital video camera that does not have the recording medium will be described.

  In FIG. 1, reference numeral 101 denotes an image pickup unit, and 102 denotes a video encoding processing unit that encodes a video signal from the imaging unit 101 by the MPEG system and decodes an encoded video signal from the multiplexing processing unit 104 during reproduction. , 103 is a display unit for displaying the video from the imaging unit 101 or the reproduced video, and 104 is a multiplexed signal sequence by multiplexing the encoded video signal and audio signal in units of a predetermined amount during recording. And a multiplexing processing unit 105 that separates and outputs a packet of a video signal and an audio signal from the reproduced multiplexed signal sequence during reproduction, and 105 is a multiplexed signal sequence and an after-recording audio signal to be described later with respect to the recording medium 106. A recording / reproducing unit 106 for recording / reproducing data is a randomly accessible recording medium such as an optical disk or a semiconductor memory card. In the present embodiment, an after-recording audio signal described later can be recorded substantially simultaneously while reproducing a multiplexed signal sequence from the recording medium 106.

  Reference numeral 107 denotes a microphone. Reference numeral 108 denotes a first audio that encodes an audio signal by a high-efficiency encoding method such as the Dolby AC3 format or the MPEG2-AAC format, and decodes and outputs the high-efficiency encoded audio signal. The encoding processing unit 109 encodes the audio signal in the PCM format, and also decodes the audio signal encoded in the PCM format, and 110 the first audio encoding processing unit 108. Alternatively, one of the audio signals encoded by the second audio encoding processing unit 109 is selected and output to the multiplexing processing unit 104, and among the audio signals from the multiplexing processing unit 104, high-efficiency encoding is performed. A voice selection unit for separating and outputting a voice signal (hereinafter referred to as a first voice signal) and a PCM-encoded voice signal (hereinafter referred to as a second voice signal); Speaker for outputting an audio signal, 112 is a system controller for controlling the entire apparatus, 113 denotes an operation unit including various switches.

  Next, the operation of this apparatus will be described with reference to the flowchart of FIG. 2 while combining the system configuration diagram of FIG. 1 and the recording medium diagram of FIG.

  Currently, video / audio multiplexed signals (file_1 to file_n 301 to 304 in FIG. 3) as shown in FIG. 3 are recorded on the recording medium 106, and there is an empty area 305.

  In step S201, the user of the apparatus issues an after-recording instruction to the video / audio multiplexed signal 304 recorded on the recording medium 106 of the apparatus.

  In step S202, the recording time 306 (n_time) of the video / audio multiplexed signal 304 is calculated. In this recording time calculation method, when the video / audio multiplexed signal 304 is recorded, the recording time is measured on the apparatus side, recorded on a part of the recording medium 106, read out from the recording medium 106, and calculated. It is calculated from the total number of audio signals in the video / audio multiplexed signal 304 and the encoding bit rate.

  In step S203, the number of bits in the free area 305 of the recording medium 106 is calculated.

In step S204, the recording time when an audio signal is recorded in the free space 305 of the recording medium 106 in the PCM format is calculated. Here, if the number of bits in the free area 305 of the recording medium 106 is extra_bit [bit], the encoding bit rate of the PCM format is about 1.5 Mbps, although there are some differences depending on the sampling frequency. The time 307 (pcm_time) during which the PCM signal can be recorded in the empty area 305 is
pcm_time [sec] = extra_bit / 1.5M
Is calculated.

In step S205, the recording time when the audio signal is recorded in the free space 305 of the recording medium 106 in the AC3 format is calculated. Similarly to step S204, when the bit number of the free area 305 of the recording medium 106 is extra_bit [bit] and the encoding bit rate of the AC3 format is ac3_brt [bit / sec], an AC3 signal is sent to the free area 305 of the recording medium 106. The recordable time 308 (ac3_time) is ac3_time [sec] = extra_bit / ac3_brt
Is calculated.

  Next, the following operations are performed according to the values of the parameters calculated in steps S202 to S205.

  If it is determined in step S206 that the time 308 during which the AC3 signal can be recorded in the empty area 305 of the recording medium 106 is shorter than the recording time 306 of the video / audio multiplexed signal 304, the video / audio multiplexed signal 304 is post-recorded. The capacity of the recording medium 106 is insufficient. Therefore, in this case, post-recording to the video / audio multiplexed signal 304 is prohibited. This mode is called after-recording prohibition mode.

  If it is determined in step S206 that the time 308 during which the AC3 signal can be recorded in the empty area 305 of the recording medium 106 is longer than the recording time 306 of the video / audio multiplexed signal 304, the video / audio multiplexed signal 304 is post-recorded. The recording medium 106 has a sufficient capacity. Therefore, in this case, post-recording to the video / audio multiplexed signal 304 is enabled.

  In step S206, when dubbing to the video / audio multiplexed signal 304 becomes possible, the mode for performing dubbing is switched in consideration of the recording time of the audio signal in the empty area 305 of the recording medium 106.

  If it is determined in step S207 that the time 307 in which the PCM signal can be recorded in the free area 305 of the recording medium 106 is shorter than the recording time 306 of the video / audio multiplexed signal 304, the video / audio is stored in the free area 305 of the recording medium 106. A PCM signal for the same time as the multiplexed signal 304 cannot be recorded. In the after-recording mode, the after-recording audio signal is encoded and recorded in the PCM format, but since there is no area for recording the PCM signal, it must be directly encoded in the AC3 format. Therefore, the audio signal of the video / audio multiplexed signal 304 cannot be reproduced by this apparatus which cannot perform AC3 encoding / decoding simultaneously. In other words, when performing post-recording on the video / audio multiplexed signal 304, the audio / video multiplexed signal 304 is not reproduced, so that the audio signal multiplexed on the video / audio multiplexed signal 304 is not reproduced. Play only the signal. The user of this apparatus performs the after-recording of the audio signal in the absence of the reproduced sound of the audio signal while watching the video signal of a viewer or the like provided in the digital video camera. This mode is called an after-recording mode without a voice monitor.

  The operation of the speech coder and speech decoder in this apparatus at this time will be described with reference to FIG. 401 is an after-recording state, and becomes high when an after-recording instruction is given to the apparatus. 402 is the state of the speech decoder, 403 is the state of the first speech encoding processing unit 108, 404 is the state of the second speech encoding processing unit 109, and 402, 403, and 404 are respectively It becomes high when the encoding process and the decoding process are executed. Further, since the time from the after-recording start point to the after-recording end point is the same as the recording time of the video / audio multiplexed signal 304, it is represented as n_time in FIG.

  When the after-recording instruction 401 is low for this apparatus, since the audio of the video / audio multiplexed signal 304 is not reproduced and after-recording is not performed, all the audio encoders / decoders are not processing. When the post-recording instruction 401 is high, the audio of the video / audio multiplexed signal 304 is not reproduced, and the second encoder encodes the post-recording signal, so only the second audio encoding processing unit 109 performs the processing. Will be going.

  If it is determined in step S207 that the time 307 during which the PCM signal can be recorded in the free area 305 of the recording medium 106 is longer than the recording time 306 of the video / audio multiplexed signal 304, the free area 305 of the recording medium 106 PCM signals for a longer time than the video / audio multiplexed signal 304 can be recorded. In this after-recording mode, a second audio signal obtained by encoding the after-recording audio signal by a light processing encoding method such as the PCM format is recorded on the recording medium 106 while reproducing the audio signal of the video / audio multiplexed signal 304. Keep it. At this time, when performing post-recording on the video / audio multiplexed signal 304, the post-recording is performed in a state where there is an audio monitor, so both the audio signal and the video signal multiplexed in the video / audio multiplexed signal 304 are performed. Play. The user of this apparatus performs the audio signal dubbing while listening to the reproduced sound of the audio signal while watching the video signal of a viewer or the like provided in the digital video camera.

  When the after-recording is completed in this way, the system controller 112 controls the recording / reproducing unit 105 to read out the second audio signal recorded in the empty area 305 of the recording medium 106. The reproduced second audio signal is output to the audio selection unit 110 via the multiplexing processing unit 104. The voice selection unit 110 outputs the second voice signal to the second voice encoding processing unit 109, and the second voice encoding processing unit 109 decodes the second voice signal that has been PCM encoded. Output to the first speech encoding processing unit 108. The second audio signal is encoded by the first audio encoding processing unit 108 in the AC3 format, which is the same format as the audio signal multiplexed on the video / audio multiplexed signal 304, and passes through the audio selection unit 110. And output to the multiplexing processing unit 104. The multiplexing processing unit 104 divides the AC3-encoded second audio signal into packet units of a predetermined amount, sends it to the recording / reproducing unit 105, and records it on the recording medium 106 by the recording / reproducing unit 105. At this time, it is also possible to overwrite-record in the area where the original PCM-encoded second audio signal was recorded. This mode is called an after-recording mode with a voice monitor.

  The operation of the speech encoding circuit and speech decoding circuit in this apparatus at this time will be described with reference to FIG. Reference numeral 501 denotes an after-recording state, which becomes high when an after-recording instruction is given to the apparatus. Reference numeral 502 denotes a state of decoding processing by the first speech encoding processing unit 108, reference numeral 503 denotes a state of encoding processing by the first speech encoding processing unit 108, and reference numeral 504 denotes a second speech encoding processing unit 109. , And 502, 503, and 504 become high when the respective encoding processing and decoding processing are executed. Further, since the time from the after-recording start point to the after-recording end point is the same as the recording time of the video / audio multiplexed signal 304, the point indicated as n_time in FIG. 5 is the same as FIG.

  When the after-recording instruction 501 is low for this apparatus, the audio of the video / audio multiplexed signal 304 is reproduced and no after-recording is performed, so only the decoding processing by the first encoding processing unit 108 is performed. When the post-recording instruction 501 is high, the audio of the video / audio multiplexed signal 304 is reproduced, and the second encoding processing unit 109 encodes the after-recording signal in the PCM format, so the first audio encoding processing unit That is, the decoding process by 108 and the encoding process by the second speech encoding processing unit 109 are performed, and the encoding process by the first speech encoding processing unit 108 is not performed. When the after-recording is completed, the decoding process by the first audio encoding processing unit 108 and the encoding process by the second audio encoding processing unit 109 are completed, and the second audio signal read from the recording medium 106 is stored. Since encoding is performed by the first speech encoding processing unit 108, encoding processing by the first speech encoding processing unit 108 is performed.

  A second embodiment will be described with reference to the drawings. FIG. 6 is an overall system configuration diagram in the second embodiment, and the basic configuration is the same as that of the first embodiment. FIG. 7 is a diagram showing an operation state of each block of the present apparatus during post-recording.

  The second embodiment shows a preferred embodiment for performing post-recording while reproducing an audio signal recorded on a recording medium in a digital video camera similar to the first embodiment.

  In FIG. 6, reference numeral 601 denotes a microphone provided in the digital video camera, 602 denotes an A / D converter that digitizes an analog audio signal obtained from the microphone 601, 603 and 606 denote switches, and 613. 614 is an internal memory, 604 is a first speech coder, 605 is a second speech coder, and the speech signal is a first speech coder 604 and a second speech coder. The data is encoded by the device 605 and once stored in the internal memory 614. Also, the speech encoded signal encoded by the first speech encoder 604 is temporarily held in the internal memory 613 and the memory 614. The first audio encoder 604 is an audio encoding circuit that encodes with a high-efficiency encoding method such as the Dolby AC3 format or the MPEG2-AAC format. During normal shooting, the first audio encoder 604 is used. In the second embodiment, the encoding method in the first audio encoder 604 is AC3. The second speech coding circuit 605 is a speech coding circuit that performs coding in the PCM format. Reference numeral 607 denotes an internal memory that exists in the digital video camera apparatus, and temporarily holds the encoded signals encoded by the first audio encoder 604 and the second audio encoder 605. Reference numeral 608 denotes a recording medium for recording a video signal, an audio signal, and a multiplexed signal obtained by multiplexing the video signal and the audio signal, and the audio encoded signal and the video encoded signal held in the internal memory 607 are multiplexed (not shown). And multiplexed on the recording medium 608.

  Reference numeral 609 denotes an audio decoder which decodes an audio signal recorded on the recording medium 608 and an audio signal obtained by separating the multiplexed signal by a demultiplexing circuit (not shown). Reference numeral 610 denotes a D / A converter, and reference numeral 611 denotes a speaker provided in the digital video camera. The digital audio signal decoded by the audio decoder 609 is converted into an analog audio signal by the D / A converter 610. An audio signal is reproduced through the speaker 611.

  Reference numeral 612 denotes a system controller. In addition to a function of controlling the entire apparatus such as writing to and reading from a memory existing in the apparatus including the internal memories 607, 613, and 614 and a recording medium 608, a switch 603 and a switch When the speech signal is encoded, the first speech coder 604 and the second speech coder 605 are switched.

  Next, the operation of this apparatus will be described with reference to the system configuration diagram of FIG. 6, the recording medium diagram of FIG. 3, and the operation chart of FIG. Note that the after-recording prohibition mode and the non-monitoring after-recording recording mode are the same as those in the first embodiment, and are therefore omitted.

  The operation in the after-recording recording mode with an audio monitor will be described with reference to FIG. Reference numeral 701 denotes an after-recording state, which becomes high when an after-recording instruction is issued to the apparatus. 702 is the state of the speech decoder 609, 703 is the state of the first speech encoder 604, 704 is the state of the second speech encoder 605, and 702, 703, and 704 are the respective states. High when the encoder and decoder are running. Further, since the time from the after-recording start point to the after-recording end point is the same as the recording time of the video / audio multiplexed signal 304, the point described as n_time in FIG. 7 is the same as FIG.

  If there is an after-recording instruction for this apparatus, 701 becomes low, only the audio decoder 609 performs processing, and only the audio of the video / audio multiplexed signal 304 is reproduced. At this time, the processing amount of the speech decoder 609 is simplified so as to be about half that of normal decoding. For example, there is a method of performing decoding on encoded data thinned out for each access unit, but the method of realizing the method is not limited here. Note that with the method of thinning out for each access unit, the playback sound becomes interrupted sound, so it is necessary to adjust well in the audio interface part.

  When the after-recording instruction 701 becomes high, the after-recording audio signal is processed by the second audio encoder 605 while the encoded audio signal of the video / audio multiplexed signal 304 is reproduced by the simple processing of the audio decoder 609. It records on the recording medium 608 as a PCM format. The PCM signal continues to be recorded on the recording medium 608 as it is. When the code amount of the PCM signal recorded on the recording medium 608 reaches the MAX value 706 which is a specified amount, 703 becomes high and is recorded on the recording medium 608. The PCM signal is read from the recording medium 608 and written back to the recording medium 608 as an AC3 format by the first speech encoder 604.

  At this time, since the speech decoder 609 is operating, in a device in which the encoder and the decoder cannot be executed at the same time, the first speech encoder 604 has only about half of the specifications at the time of normal encoding. Can't work. Therefore, the PCM signal read amount from the recording medium 608 is read and divided by half the amount of writing to the recording medium 608 for encoding.

  In this state, 702 continues to reproduce the sound while being high until an after-recording end (or after-recording pause) command is given, and the signal encoded in the AC3 format among the PCM signals recorded on the recording medium 608 Is considered to have been erased from the recording medium 608, there is a point where the PCM recording area on the recording medium 608 becomes zero, as in 705. At that point, since there is no PCM signal to be converted to AC3, the first encoder 604 stops. When an after-recording instruction is given to the apparatus again and 701 becomes high, the above operation is repeated.

  When an after-recording end command is given to this apparatus, 701 becomes low, and the speech decoder 609 stops and playback of the speech signal ends. However, until the 705 becomes zero, the first speech encoder 604 The dubbing is finished when it continues to operate and reaches zero.

  In FIG. 7, an area 705 recorded by PCM on the recording medium 308 indicates an area where the PCM signal is recorded on the recording medium 308. The area 705 rises at the same time as the post-recording instruction, but when the MAX value 706 is reached, AC3 In order to start the conversion to, the rising curve of the PCM recording area on the recording medium 308 becomes loose. When an after-recording stop or end command is given, 705 decreases, but the curve becomes looser than the curve at the after-recording start point.

  By performing the above control, it is possible to realize a dubbing with a voice monitor.

System configuration diagram for explaining the first embodiment Operation flowchart in the after-recording mode in the first embodiment File structure diagram of recording medium in the first and second embodiments Operation chart of each block in the after-recording mode in the first embodiment Operation chart of each block in the after-recording mode in the first embodiment System configuration diagram for explaining the second embodiment Operation chart of each block in the after-recording mode in the second embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Image pick-up part 102 Image | video encoding process part 103 Display part 104 Multiplexing process part 105 Recording / reproducing part 106 Recording medium 107 Microphone 108 1st audio | voice encoding process part 109 2nd audio | voice encoding process part 110 Audio | voice selection part 111 Speaker 112 System Controller 113 Operation Units 301 to 304 Video / Audio Multiplexed Signal 601 Microphone 602 A / D Converter 603 Switch 604 First Audio Encoder 605 Second Audio Encoder 606 Switch 607 Internal Memory 608 Recording Medium 609 Audio Decoder 610 D / A
611 Speaker 612 System controller 613 Internal memory 614 Internal memory

Claims (16)

The multiplexed signal sequence is reproduced from a recording medium in which the encoded video encoded signal and the first audio signal encoded by the first audio encoding method are recorded as a multiplexed signal sequence. Playback means to
First audio decoding means for decoding a first audio signal in the multiplexed signal sequence reproduced by the reproduction means;
Voice input means for inputting a second voice signal;
Second speech encoding means for encoding the second speech signal input by the speech input means by a second speech encoding method having a smaller calculation amount than the first speech encoding method;
Recording means for recording the second audio signal encoded by the audio encoding means on the recording medium;
In an after recording mode in which an after-recording audio signal to be reproduced is recorded instead of the first audio signal, the reproduction process of the multiplexed signal sequence by the reproducing unit and the first audio signal by the first audio decoding unit The second audio encoding means performs the encoding process while performing the decoding process, and the second audio signal encoded by the second encoding method is recorded on the recording medium. A recording apparatus comprising: a second audio encoding unit; and a control unit that controls the recording unit.   Second speech decoding means for decoding the speech signal encoded by the second speech encoding method; and first speech encoding means for encoding the speech signal by the first speech encoding method. And the control means further decodes the second audio signal reproduced by the reproduction means by the second audio decoding means, and then converts the decoded second audio signal to the first audio signal. 2. The recording apparatus according to claim 1, wherein the second audio encoding unit and the recording unit are controlled so as to be encoded by the encoding unit and recorded again on the recording medium.   The recording means includes a second area encoded by the first audio encoding means for a recording area in which the second audio signal encoded by the second audio encoding method has been recorded. The recording apparatus according to claim 2, wherein the audio signal is recorded.   After the recording of the second audio signal encoded by the second audio encoding unit is completed, the second audio signal is reproduced and decoded by the second audio decoding unit and the first audio signal is decoded. The recording apparatus according to claim 2, wherein the recording apparatus performs recording by the voice encoding means and records on the recording medium.   2. A calculating means for calculating a recordable time in the unrecorded area using the unrecorded area of the recording medium and the bit rate of the first or second audio encoding method. The recording device described.   The said control means determines permission or prohibition of after recording according to the recordable time to the unrecorded area | region in the said recording medium, and the recording time of the said video / audio multiplexed signal. Recording device.   The control means permits after-recording when the recordable time when the audio signal encoded according to the first audio encoding method is recorded in the unrecorded area is longer than the recording time of the multiplexed signal sequence. The recording apparatus according to claim 6.   The control means is further configured such that when a recordable time when an audio signal encoded according to the second audio encoding method is recorded in the unrecorded area is shorter than a recording time of the multiplexed signal sequence, 8. The recording apparatus according to claim 7, wherein the second audio signal is recorded as after-recording audio without reproducing the first audio signal.   2. The recording apparatus according to claim 1, wherein the recording unit records time stamp information added to the second audio signal.   11. The recording apparatus according to claim 10, wherein the recording unit records the time stamp information in synchronization with the multiplexed signal sequence reproduced by the reproducing unit.   2. The recording apparatus according to claim 1, wherein the video signal is encoded by an MPEG system.   The recording apparatus according to claim 1, wherein a decoding processing amount in the first speech encoding method is substantially the same as a processing amount required for encoding.   The recording apparatus according to claim 1, wherein the first speech encoding method is a Dolby AC3 method.   The recording apparatus according to claim 1, wherein the second speech encoding method is a PCM (Pulse Code Modulation) method.   The recording apparatus according to claim 1, wherein the recording medium is an optical disk.   The recording apparatus according to claim 1, wherein the recording medium is a random access medium.

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